Hall B Status

CLAS Collaboration MeetingOctober , 2004

Volker D. BurkertJefferson Lab

Run statusPublication status/analysisStatus of new projects2005/2006 tentative run plan 12 GeV Upgrade

Nobel Prize in Physics 2004

D. GrossUCSB

D. PolitzerCALTECH

F. WilczekMIT

“Asymptotic Freedom”

unexplored

Hall B Status Overview

23 major CLAS production runs completed – e1a/b, g1a/b, g6a, e1c, e2a, g6b, g2a, g1c, g3, e1d, e5, eg1b, g8a, g6c, e1-6,

e6, e2b, g7, e1e, e1f/g, eg2, g10, g11 (+2 non-CLAS experiments: g5, rad-φ)

Running experiment – PRIMEX

Publications – 17 technical papers published – 32 physics papers published/accepted in PRL, PRC, PRD (3 CLAS related papers)– 8 submitted (incl. 3 CLAS related papers)– 3 in collaboration review

Projects in preparation for new experiments- PRIMEX- DAQ Upgrade to 10KHz rate (EG3)- DVCS S.C. Solenoid and PbWO4 EC (Accessing GPDs)- BoNus detector (Neutron structure function) - Frozen Spin Target (search for missing N*’s)- Cerenkov counter for one CLAS sector (small Q2 GDH) - Polarimeter for linearly polarized photons (g8)

12 GeV Upgrade on track to CD-1

Technical Publications• Torus Magnet IEEE Mag.25 (1989) 1902• Drift Chambers

– construction Mac Mestayer NIM A323 (1992) 191– update Mac Mestayer NIM A367 (1995) 316– Region I Dan Carman NIM A419 (1998) 315– Region II L.M. Qin NIM A411 (1998) 265– Summary Dan Carman NIM A449 (2000) 81

• Cerenkov Counter Paul Stoler NIM A465 (2001) 414• TOF Counters Elton Smith NIM 432 (1999) 265• Start Counters Simon Taylor NIM A462 (2001) 484• Forward Cal. Cole Smith NIM A460 (2001) 239• Large Angle Cal. Mauro Taiuti NIM A447 (2000) 431

Response Mauro Taiuti NIM accepted (2004)• Tagging System

– window Jim O’Brien NIM 421 (1999)– tagger Jim O’Brien NIM 440/2 (2000) 263

• Polarized target Chris Keith NIM A501 (2003) 327• FST coil design O. Dzyubak NIM A526 (2004) 132• CLAS Overview Bernhard Mecking NIM A503 (2003) 513

Hall B Physics Publications (PRL/PRC/PRD)

η-Electroproduction in the S11(1535) region, PRL86 (2001) 1702Double Spin Asymmetry in ep->eπ+n, PRL88 (2002) 082001N->∆(1232) Multipoles from p0

Electroproduction, PRL88 (2002) 122001QED Radiative Corrections in Exclusive PionElectroproduction PRD66 (2002) 074004η-Photoproduction on the Proton, PRL89, (2002) 222002-1 Polarisation transfer in ep->eK+Λ , PRL90,131804 (2003), Single Quark Transition Analysis of N* Excitations in [70,1-], PRC67, 035204 (2003)ep -> epπ+π− and baryon resonance analysis, PRL91, 022002-1(2003)First measurement of beam-target spinasymmetry in ep->epp0, PRC 68, 035202

Hadron Structure & Spectroscopy Measurement of σ LT’ in the ∆(1232) regionPRC {\bf 68}, 032201 (2003) Evidence for an Exotic Baryon State withS=+1, on Deuterium PRL 91, 252001 (2003)Photoproduction of K+Λ/Σ , PRC-RCnucl-ex/0305028 (2003)Electroproduction of ep -> enπ+ in the firstand second resonance region, CLAS reviewSingle Spin Asymmetry in ep -> eπ+n , in the ∆(1232) region, PRC-RCPhotoproduction of cascades from protontargets, PRD subm.σL/σT for p(e,e’K)Λ from polarization transfer nucl-ex/0402024.Evidence for Θ+(1540) excitation on protons, PRL 92, 0322001 (2004).Electroproduction of ∆, P11, S11, D13 , at Q2 = 0.4, 0.65 GeV2, PRC subm. First Observation of Exotic Mesons in PhotoproductionElectroproduction of η and evidence for a p-wave resonance.

32 - published (3) 8 - submitted (3)3 - in collaboration review

Physics analysis papers of CLAS members based on CLAS data.

3 - published3 - submitted

Structure Functions & Hard Processes

Inclusive spin structure function in eD -> eX, PRC67, 055204 (2003)F2 and Moment analysis in ep-> eX, PRD 67 (2003) Inclusive double polarisation asymmetry, g1, Γ1p, PRL 91, 222002.φ-Photoproduction at large t, PRL85 (2000) 4682φ-Electroproduction, PRC63 (2001) 065205-1K+Λ(1520) Electroproduction, PRC63 (2001) 044601ρ0-Photoproduction, PRL87 (2001) 172002Beam Asymmetry in DVCS PRL87 (2001) 182002 Photoproduction of ω mesons at high t, PRL90, 022002-1 (2003)Beam Single Spin Asymmetry in ep->eπ+X in the DIS kinematics, PRD 69, 112004 (2004), hep-ex/0301005Deeply exclusive ρ0 production, PRL submitted Tensor Polarization of the φ meson photo-produced at high t, PRC 69, 032203(R) (2004).

Hall B Physics Publications – cont’d

Twist analysis of Γ1p(Q2), PRL subm. Bjorken Integral Γ1(p-n) from inclusivepolarized structure functions g1p, g1n , PRL (2004)

Hall B Physics Publications – cont’d

Nuclear Processes

Photofission of Heavy Nuclei, PRL84 (2000) 5740Photofission of Heavy Nuclei, PRC65, 044622 (2002) Nuclear Scaling in A(e,e’) at x>1, PRC 68, 014313 (2003)Two-Nucleon Momentum Distributions in 3He(e,e’pp)n, PRL 92, 52303 (2004).Deuteron Photo-disintegration, PRC (2004)Deuteron Photo-disintegration PRL, submitted.Proton source size in eA -> eppX, PRL acceptedSurvey of beam asymmetries in semi-inclusive scattering on 4He or 12C.Complete measurement of 3-body photodisintegration of He-3 for photon energies between 0.55 and 3 GeV, PRC submitted

Hall B Physics Publications (PRL,PRC,PRD)

5

10

15

published

submitted

year2000 2001 2002 2003 2004

Hall B Publication Overview PRL, PRC, PRD

Spectroscopy & Structure

Hard scattering& Structure F.

Nuclear processes

Sum

2000 - 1 1 2

2001 1 4 - 5

2002 4 - 1 5

2004 4 + 2 + 3 3 + 2 + 1 2 + 3 8 + 8 + 4

Sum 13 + 2 + 3 12 + 3 + 1 6 + 3 30 + 8 + 4

2003 4 4 2 10

Published/accepted submitted in review

Physics Impact of CLAS Data IPaper Physics #citations (>30)

10/13/04

• PRL 85 (2000) 4682 φ-Photoproduction at high t 35

• PRL 86 (2001) 1702 Study of S11(1535) in η electroproduction 31

• PRL 87 (2001) 182002 Deeply Virtual Compton Scattering 98

• PRL 88 (2002) 182002 Multipoles in the γ*N∆(1232) transition 40

• PRL 91 (2003) 252001 Evidence for an S=+1 Exotic Baryon State on deuterium 287

• PRL 92 (2004) 32001 Evidence for an exotic Baryon with S=+1 on Protons 147

CAA

CAA

CAA

Physics Impact of CLAS Data IIPaper Physics #spires citations

per month (>0.7)

• PRD 67 (2003) 092001 Kinematically complete measurement of F2 0.8

• PRL 87 (2001) 182002 Deeply Virtual Compton Scattering 2.6

• PRL 88 (2002) 182002 Multipoles from γ*N∆(1232) transition 1.1

• PRD69 (2004) 112004 SSA in SIDIS ep -> eπ+X 1.3

• PRL 91 (2003) 252001 Evidence for exotic baryon on deuterium 19.0

• PRL 92 (2004) 032001 Evidence for exotic baryon on protons 13.1

• PRL 91 (2003) 222002 Measurement of polarized structure function g1 0.8

CAA

CAA

CAA

CAA

CAA

Summary of Events since last CLAS Meeting

PAC26 – two proposals for Hall B, two LOI’s

PR-04-116 W. Brooks 5 days (35) A-PR-04-102 jeopardy D. Sober 9 days (19) B+

Completed G11 run (Θ+ search and excited states on hydrogen)=> Talks on G10, G11 analysis status

Repairs of drift chambers in five sectors R2/R3 The electronics corrosion problem seems to have stoppedCurrent repairs due to broken wires, HV disconnects, other electronics problems.

PrimExInstallation of HyCal and experimental infrastructureStarted PrimEx Engineering Run and Physics Run

Preparations for CD-1 (Allison Lung’s presentation) Update of physics case for Hall B => afternoon session organized by LatifaExperimental equipment => talk by Will

pair spectrometer detectors

photon

beam

Photon Calorimeter

pair spectrometer

lead-tungstate

target

PrimEx ExperimentPurpose: Precise measurement of the π0

lifetime using the Primakoff process. Absolute cross section measurement.

Hybrid Calorimeter (HyCal)Needed to reconstruct π0 −> γγ events

PrimEx – Run

Commissioning completed

All ~ 2000 channel operational

Gain matching of all PbWO4 crystals and all Pb-glass countersin direct photon beam.

Trigger uniformity studies

Tagging efficiency measured

Problems with Pair spectrometer power supply (was fixed yesterday)

Production run started

PrimEx – Energy Trigger Trigger: Total energy in HyCal

Cluster energyTriggerthreshold

E(GeV)

PrimEx – Compton Events

Compton event candidate γe γe event

back-to-back

PrimEx – Energy Trigger Hit distribution on HyCal front face

PrimEx – Production Events

“I have seen billions of π0 on my plot, but these thirty are most exciting”

Ilia Larin, 10/14, 00:53hrs.

e-mail message by

First π0 events

Congratulations!

CLAS - DVCS Experiment Superconducting solenoid: needed for shielding Moller electronsPbWO4 e.m. calorimeter needed for photon detection

calorimeter

coil windings

cryostat

Solenoid under construction

Cold test Nov ‘04 at Saclay.

CLAS - DVCS Experiment

Effect of Solenoid Field on Moeller Electrons

Solenoid field OFF Solenoid field ON

CLAS - DVCS Experiment

Solenoid Coil in preparation for cold test at Saclay

CLAS - DVCS Experiment

Orsay – CAD view of assembled calorimeter with support arms,with top removed.

CLAS - DVCS Experiment

DVCS - Calorimeter framesand mounting of MotherboardAt Orsay

PbWO4 crystals in preparation for assembly at JLab.

APD’s

Wrapping assemblyfor ~ 20 crystals

CLAS - DVCS Experiment Solenoid:

Magnet coil currently being prepared for cold test planned for early November at Saclay

If no major problems occur the magnet should arrive at JLab early December.

Electronics and support frames:Test of all electronics channels to begin this weekFrames to be shipped to JLab early November

Laser monitoring system: Completed

Lead-tungstate crystals:Wrapping channel assembly, APD gluing, well underway Calorimeter assembly can start as soon as frames arrive

π0 γγ Reconstruction in DVCS EC - Beam Test

(100 PbWO4 crystalsprototype)

σ=8.6MeV

Beamposition

Iterative π0 mass calibration

σ=12MeV

CLAS - BoNuS Experiment

Measurement of “Free” Neutron Structure Function F2n

Prototype RTPC thoroughly tested

Design of final RTPC and support almost finished (with P. Hemler)

TPC Readout• Received and tested first front-end electronics card from CERN (ALICE

TPC FEC) • Working decision to integrate TPC readout into CLAS VME controller

software• Design of signal transmission electronics from TPC to FEC input using

long cables and transmitter/inverter and receiver cards tested successfully (together with JLab fast electronics group)

Software for track reconstruction being created and tested (including integration of wire chamber data for cosmic ray data)

Track Finding Code Development

Cosmic ray passing through the prototype RTPC with 4x4 readout pad geometry

Size of the green squares correspond to amount of charge collected on pad for a given 100 nsec time interval

Drift Time [100 nsec]

CLAS Collaboration Meeting October 14 - 16, 2004

Near- and Long-Term BoNuS Plans

• Finish second prototype RTPC at ODU (radial drift length increases from 2 cm to 3 cm for more track length)

• Design and build readout pad board with complete pad coverage for prototype RTPC

• Set up complete DAQ system based on CLAS CODA with VxWorks at ODU• Continue design of final RTPC and gas target (integration into CLAS)• Plan another test run with slow protons at TUNL for late 2004 or early 2005

Upgrade to more than 16 readout channels (ALICE FEC and USB-RCU)Use prototype with 3 cm drift region

More track information and longer tracks as input for analysis software presently under development

• Test run of pRTPC inside Møller solenoid in conjunction with DVCS experiment in spring 2005

• Ready for data taking in fall 2005

Frozen Spin Target for CLASTechnical problem:- build polarized target for tagged

photon beam - minimum obstruction of CLAS solid angle

- low distortion of particle trajectories in magnetic field

5 Tesla polarizing magnet

CLA

S

JLab design

CLAS Frozen Spin Target Progress

• outer vacuum can fabricated and leak tested

• 4.2K and 1.5K pre-cooling stages under construction

• mixing chamber design finalized, under construction

• all components (electronics, pumps, etc.) in-house

• sintered silver heat exchangers under construction (2 of 5 complete).

• refrigerator pump set assembled

• 3He gas handling system complete

• 4He gas handling system under construction

• short (10cm) solenoid designed, fabricated, test in progress

• preliminary design work on insertion cart and target positioning system

• polarizing magnet positioning system completed

• work on the transverse coil continues

Tagger energy calibration

Microstrip detectors20x20 mm, 50µm pitch

e+

e-

Bo

0.5Bo

Photon converter target

electrons

Tagger focal plane energy counters

pair spectrometer magnet

Triggerdetector

radiator

Tagging system

endpointNe+e-

E counter

Triggerdetector

Note: In reality pair spectrometer deflects in horizontal plane. Shown here as vertical deflection, for clarity.

Photon Endpoint Energy Calibration

3 out of 11 runs near Endpoint energy.

- With increasing distance between the e+ and the e- measured in the microstrip detectors,the magnetic field, corresponding to the beam energy increases.

Hall B Run PlanRun Run PAC Target Energy Electron Commentgroup time rating (GeV) polar.

PrimEx 22 A nuclear >5 - HyCal2γ test 1 **) A- ? 5.75 Needs justificationeg3-cascade 20 A D2 >5.75 - DAQ upgradeE1-DVCS(a) 40-50 *) A H2 >5.75 High SC Solenoid, PbWO4 EBoNuS test 5 **) A- D2 4.5 - SC SolenoidG8b 29 A- H2 4.5 - Goniometer, polarimete-----------------------------------------------------------------------------------------------------------------------------

EG4-GDH 20 A NH3 1.2-4.0 High New CerenkovE8-BoNuS 25 A- D2 gas 4 & 6 No Radial TPCEG5-Frozen 47 A- Butanol various High Frozen spin targetG12 35 A H2 >5.75 No New Start Counter ?E1-DVCS(b) 10-20 A H2 >5.75 High Solenoid, PbWO4 - ICE7 (coherent ρ) 50 A- D2 >5.75 High uses DVCS solenoid2γ experiment 5 A- H2 >5.75 No Major change in set upEG2b 11 B+ nuclear > 5 No

Σ (unscheduled) 334 (252)

*) Expect higher efficiency due to single Hall operation (60-75%)**) at the discretion of management - needs justification for approval

Hall B 2004-2006 Schedule - Tentative

Date Experiment days Energy (GeV) Rating Polarization?-------------------------------------------------------------------------------------------------------------------------10/01 - 11/24/04 PRIMEX 5.75 A -12/02 – 01/30/05 eg3-cascade 20 5.75 A -

02/01 - 03/10/05 DVCS installation03/11 - 05/08/05 E1-DVCS(a) 40-50 5.75 A High06/02 - G8 29 4.5 A- -

Unscheduled 2005/2006EG4-GDH 20 1.2–5.0 A HighE8-BoNuS 25 4 & 5.75 A- -EG5-Frozen 47 various A- HighG12 35 5.75 A -TPE 5 >5.75 A- -

12 GeV Upgrade

=> Presentation by Allison Lung (Project Director)

Major Goal: CD-1 in FY2005

Sequence of events:

⇒ Conceptual Design Report for the CEBAF Upgrade to 12 GeVoutlining the science and equipment (~40 pages document).

⇒ First draft January 2005⇒ Internal review⇒ Final draft in spring 2005

⇒ DOE science review: February – June 2005⇒ Lehman Review of Upgrade Project: July 2005⇒ CD-1 approval September 2005 (Goal)

What does this mean for Hall B?

Need to update the Equipment & Science in Hall B pCDR

Re-establish Hall B Upgrade working groupsFive WGs for physics in Hall B, NP12 workshop on nuclear physics at 12 GeVWGs for equipment in Hall B, revised cost estimate. We should broaden collaborator involvement in defining equipment.

Prepare updated Hall B pCDR

11/30/04 Updated Science motivation in Hall B pCDR12/06/04 Submit requests for PAC27 presentations to enhance specific

physics programs or add new programs not included in JLABpCDR. Should emerge from new physics working groups.

12/18/04 Review of Science & Equipment for Hall B Upgrade.01/14/05 PAC27 – Continue science review & equipment matching02/xx/05 Revise Hall B pCDR

Input into JLAB CDR.

Physics Working GroupsWhat should the Physics Working Groups achieve?

Put together a new version of Hall B pCDRFeed material to the editorial board of JLAB pCDR.Prepare material for presentations of new programs to PAC27

What to we need to have for PAC27? Each WG should prepare the following materials

a prioritized physics program that can be carried out inone(two) year(s) (1 year = 2500 hrs at 100% efficiency)at a ep(A) luminosity of L= 1(2)x1035 cm-2s-1

Identify the detector components needed for the programPrepare appealing graphs/tables showing the expected data and physics results, especially demonstrating the full scope of results achievable with the Hall B upgrade, i.e. all kinematicsdependencies xB /W, Q2, t, φ; simultaneous measurement of several processes, e.g: ep-> epγ, enρ+, epρ0, epω, enπ+, .. etc.Discuss the expected novel physics results and their impact on our understanding of hadronic matter.

Demonstrate how the Hall B upgrade program as a whole providesexciting and qualitatively new insights in hadron/nuclear physics.

CLAS++

CLAS12CLAS12

OutlookWe have an excited program underway or planned in many different areas of hadronic physics. Higher level physics analysis becomes increasingly important.

We still have not solved the ~8% normalization problem observed in the g1c data. We need to address this with the new data sets.

With g10 and g11 we have by far the world largest data set on meson photoproduction on hydrogen and deuterium. This needs to be analyzed also in terms of non-pentaquark physics. Excited hyperons and N*’ are abundant in these data sets

Any new proposal for PAC27 should be evaluated if it fills agap in our program that is important to fill. We need to think carefully what enhances the CLAS program and can also run on a short time scale.

Started work on the next phase (CD-1) of the 12 GeV upgrade to ensure a brilliant future of our exciting program. We now need to move towards a broader involvement of collaborators in hardware and software projects, and a more formal structure in this effort. Define responsibilities of collaborating institutions, MOU’s, etc. , ..